This invention pertains to the consolidation or strengthening of unconsolidated sand-like material in a subsurface formation near the borehole of a water, oil or gas well. More particularly, an organic silicate alcohol solution is injected into a subsurface formation to thereafter react with water and consolidate the formation while leaving it permeable to the flow of water, oil or gas from the formation.
Many processes have been proposed for consolidating sands in a subsurface formation. For example, U.S. Pat. No. 3,592,267 discloses the use of an emulsion of an aqueous solution of an alkali metal silicate in a hydrocarbon liquid followed by an aqueous solution containing a silicate precipitator. Alkali metal silicates are soluble in water and require precipitation or reaction with special substances to set up. The method of U.S. Pat. No. 3,592,267 also has the usual drawbacks of creating and handling an emulsion. For example, there is less flexibility in the formation of a stable emulsion. In addition, it is difficult to wet the sand properly with an aqueous solution of silicate when the silicate is in a water-in-oil type emulsion with the silicate solution being the suspended phase and the oil being the continuous phase. Moreover, the movement of an emulsion into the less mobile areas of the interstices of sand particles adjacent a borehole is difficult to predict.